99 Percentile Qs Bank for JEE MainPhysicsCurrent Electricity
Two batteries of emf E 1 and E 2 E 2 > E 1 and internal resistances r 1 and r 2 respectively are connected in parallel as shown in the figure. Then, which of the following statements is correct?
Options
- AThe equivalent emf E is smaller than E 1 .
- BThe equivalent emf E = E 1 + E 2 .
- CThe equivalent emf E is greater than E 2 .
- DThe equivalent emf E of two cells is between E 1 and E 2 always.
Correct answer
D. The equivalent emf E of two cells is between E 1 and E 2 always.
Step-by-step solution
The equivalent internal resistance of the two cells between A and B is R = r 1 r 2 r 1 + r 2 If E is the equivalent emf of the two cells in parallel, then E R = E 1 r 1 + E 2 r 2 = E 1 r 2 + E 2 r 1 r 1 r 2 ∴ E = ( E 1 r 2 + E 2 r 1 r 1 r 2 ) R = E 1 r 2 + E 2 r 1 r 1 + r 2 A s , E 2 > E 1 ⇒ E 1 < E < E 2 [ For all values of r 1 and r 2